With the introduction of the Merlin 45 in December 1940, a number of Spitfire Mk.I and II airframes were fitted with this more potent engine. Without the need for extensive modifications, the Merlin 45 could be fitted to airframes already on the production line. This Merlin 45 version became the Type 331 Spitfire Mk.V.
The first aircraft went to No. 92 Squadron in February 1941. As would become evident in combat, the Va's armament of eight Brownings was no match to the opponent cannon-armed Bf 109s and later the Fw 190s, so the Mk.Va production was halted after only 94 aircraft.
The Spitfire Mk.Vb, with two 20mm Hispano cannon and four Brownings, entered squadron service soon after.

Spitfire V production*:
Type 331 Spitfire Va and LF.Va: 94 aircraft.
Type 331 Spitfire Mk.Vb/Vb (Trop): 3,911 aircraft.
Type 349 Spitfire Mk.Vc/Vc (Trop): 2,467 aircraft.
* Depending on the sources used, the total Mk.V production numbers vary from 6,465 to 6,787 aircraft.


Engines for the Vb and Vb (Trop):
Merlin 46 (1,190hp/875kW); Merlin 50 (1,470hp/1,097kW); Merlin 50A (1,185hp/884kW). The addition of a new carburettor to the Merlin 45 created the Merlin 50 series. Late production Mk.Vs used the Merlin 50, 55 and 56, optimised for high altitude flying.

Engines for the LF.Vb and LF.Vb (Trop):
Merlin 45M (1,470hp/1,096kW); Merlin 50M (1,470hp/1,096kW); Merlin 55M (1,580hp/1,162kW). The M-suffix indicating that the blades of the superchargers of the engines had been cropped to optimise the aircraft for low-level operations.

The Battle of Britain Memorial Flight at RAF Coningsby has Spitfire Vb AB910 on strength. The aircraft proudly wears the colours of BM327 'SH-F' of No.64 Squadron, RAF. This aircraft saw action over the invasion beaches in Normandy on 6 June, 1944. BM327 was flown that day by F/L Tony Cooper.